Resumen Las bacterias benéficas que habitan la rizósfera de las plantas son de gran interés agrícola debido a su capacidad para producir fitohormonas durante la colonización radicular. Estas fitohormonas producen cambios fisiológicos en la planta que favorecen una mayor absorción de nutrientes que provocan un rápido crecimiento vegetativo y una mayor producción. Esta investigación tuvo como objetivo evaluar el efecto de la inoculación de dos de estas bacterias, Azospirillum sp. y Pseudomonas fluorescens en el cultivo de maíz harinoso bajo condiciones de campo típicas de la región alto andina. El experimento se realizó utilizando semilla de maíz harinoso de la variedad INIAP-101 con un diseño de bloques completos al azar y seis repeticiones. Los tratamientos correspondieron a: T1 (Azospirillum sp.), T2 (P. fluorescens), T3 (Azospirillum sp. y P. fluorescens), T4 (testigo con fertilización química convencional) y T5 (testigo absoluto). La aplicación de estas bacterias incrementó de manera significativa (p<0,05) la longitud de raíz, el diámetro de la mazorca y el rendimiento del maíz tierno (elotes o choclos). La inoculación combinada de estas bacterias (T3) obtuvo el mayor rendimiento con 19,70 t ha−1 de choclos, mientras que el testigo químico y el testigo absoluto obtuvieron 17,12 y 13,58 t ha−1 de choclos, respectivamente. El análisis económico de T3 reportó un coste/beneficio de 1,35, lo cual indicó que el sinergismo de estos dos géneros podría ser una estrategia sostenible para mejorar los rendimientos y reducir el uso de fertilizantes químicos en el cultivo de maíz de la región Andina.

Abstract Plant growth-promoting bacteria (PGPB) that inhabit root rhizosphere of plants are of great agricultural importance due to their ability to produce phytohormones during root colonization. These phytohormones produce physiological changes in the plant that favor a greater absorption of nutrients, promote growth and increase production. This study analyzed the effect of inoculation of two of these bacteria, Azospirillum sp. and Pseudomonas fluorescens, under field conditions representative of the Andean Highlands. The experiment was carried out using flour corn seed of the INIAP-101 variety in a randomized complete block design with six repetitions. The treatments corresponded to: T1 (Azospirillum sp.), T2 (P. fluorescens), T3 (Azospirillum sp. and P. fluorescens), T4 (control, conventional chemical fertilization) and T5 (absolute control). The application of these bacteria significantly increased (p<0.05) the root length, the diameter of the cob, and the yield of fresh corn (“elotes” or “choclos”). The combined inoculation of these bacteria (T3) obtained the highest yield, with 19.70 t ha−1 of fresh corn; while the chemical control and the absolute control got 17.12 and 13.58 t ha−1 of fresh corn, respectively. The economic analysis of T3 reported a benefit/cost of 1.35, which indicates that the synergism of these two bacteria could be a sustainable strategy to improve yields and reduce the use of chemical fertilizers for corn production in the Andean region.

Resumen La mastitis bovina es una enfermedad que afecta a las ganaderías de pequeños y medianos productores de los cantones Cayambe y Pedro Moncayo, Provincia de Pichincha-Ecuador. El tratamiento de esta enfermedad resulta complicado debido a la variedad de microorganismos que la provocan. El presente estudio se enfocó en la determinación molecular por medio de reacción en cadena de la polimerasa (PCR) de los agentes etiológicos de la mastitis. Esta técnica presenta múltiples ventajas al reconocer familia, género y especie de microorganismos, y es un método capaz de detectar genes de resistencia de antibióticos, lo que resulta importante al momento de diagnosticar y tratar enfermedades. El objetivo de esta investigación se centró en la identificación de bacterias causantes de la mastitis bovina, utilizando pruebas bioquímicas y moleculares. Las pruebas bioquímicas como tinción Gram, Catalasa, Coagulasa, y Agar Manitol Sal fueron eficientes para obtener cepas puras y determinar el género de algunas bacterias. Se utilizaron primers específicos (RNA16S) para la identificación molecular de 9 agentes etiológicos causantes de la enfermedad en las unidades productivas. Los microorganismos encontrados fueron; Staphylococcus pasteuri, Staphylococcus warneri, Staphylococcus sp., Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus saprophyticus, Sphingomonas sp., Streptococcus dysgalactiae, Streptococcus uberis, la mayoría presentes en mastitis clínica. Para detectar genes de resistencia se utilizaron primers específicos, de los cuales 7 muestras presentaron el gen para resistencia a blaTEM (β-lactámicos) y 6 muestras presentaron el gen para resistencia a tetA (tetraciclinas). Se identificó multirresistencia en las especies: Staphylococcus pasteuri, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus uberis, Sphingomonas sp.

Abstract Bovine mastitis is a disease that affects the farms of small and medium producers in the cantons of Cayambe and Pedro Moncayo, Pichincha Province-Ecuador. Treating this disease is not easy due to the different microorganisms that cause it. This study focused on the molecular determination by means of polymerase chain reaction (PCR) of the etiological agents of mastitis, having multiple advantages when recognizing family, gender and species of microorganisms. It is a method capable of detecting resistance genes of antibiotics, an important analysis when diagnosing and treating diseases. The aim of this research is to identify bacteria causing bovine mastitis by using biochemical and molecular tests. Biochemical tests such as: Gram staining, Catalase, Coagulase, and Mannitol Salt Agar were efficient to obtain pure strains and determine the gender of some bacteria. Specific primers (RNA16S) were used for the molecular identification of 9 etiological agents causing the disease in the productive units. The microorganisms found were Staphylococcus pasteuri, Staphylococcus warneri, Staphylococcus sp., Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus saprophyticus, Sphingomonas sp., Streptococcus dysgalactiae, Streptococcus uberis, mostly present in clinic mastitis. To detect resistance genes, specific primers were used, of which 7 samples presented the gene for resistance to blaTEM (β-lactam) and 6 samples presented the gene for resistance to tetA (tetracyclines). Multi-resistance was identified in the species Staphylococcus pasteuri, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus uberis, Sphingomonas sp.

Abstract The development of living beings depends on the health and chemical quality of the available water. In recent years, the importance of the environment in the spread of resistant and multi-resistant bacteria to antibiotics has been observed, a situation that has placed the problem of antibiotic resistance on a broader level and which is being studied from the perspective “One Health”. The objective of this work was to determine the presence of multi-resistant bacteria to antibiotics in irrigation water samples from the Chibunga river. Fourteen water samples of 100 mL each were collected in sterile containers and aseptically, were kept under refrigeration until analysis in the laboratory. Each sample was seeded by the surface seeding method on blood, cystine electrolyte deficient, MacConkey, Salmonella-Shigella and thiosulfate citrate bile sucrose agars, incubating in all cases at a temperature of 37 °C for a maximum time of 48 hours. The identification of bacterial colonies was carried out through physiological and biochemical tests according to the identification schemes indicated by MacFaddin. The resistance/sensitivity to antibiotics of the identified colonies was carried out by the disk diffusion method of Kirby Bauer. Two species of multi-resistant bacteria were identified, including strains of Morganella morgani and Plesiomonas shigelloides resistant to antibiotics of clinical use such as ceftazidime, aztreonam, ciprofloxacin, nalidixic acid and trimethoprim-sulfamethoxazole. The results show that the waters of Chibunga river harbor bacteria with multi-resistance to antimicrobials, representing a contamination risk of agricultural products harvested in its vicinity, as well as for the people who use these waters.

Resumen El bienestar y desarrollo de los seres vivos depende de la calidad sanitaria y química del agua disponible. En los últimos años se ha venido observando la importancia del ambiente en la diseminación de bacterias resistentes y multirresistentes a los antibióticos, situación que ha colocado la problemática de la resistencia en un plano más amplio y que se está estudiando desde la perspectiva “One Health”. En este sentido, el objetivo del presente trabajo fue determinar la presencia de bacterias multirresistentes a los antibióticos en muestras de agua de riego provenientes del río Chibunga. Se recolectaron 14 muestras de agua de un volumen de 100 mL cada una, en envases estériles y de manera aséptica, las cuales fueron conservadas bajo refrigeración hasta su análisis en el laboratorio. Cada muestra fue sembrada por el método de siembra en superficie en los agares cistina electrolito deficiente, MacConkey, Salmonella-Shigella, tiosulfato citrato bilis sacarosa y agar sangre, incubándose en todos los casos a una temperatura de 37 °C durante un tiempo máximo de 48 horas. La identificación de las colonias bacterianas se realizó mediante pruebas fisiológicas y bioquímicas de acuerdo con los esquemas de identificación indicados por MacFaddin. El perfil de susceptibilidad a los antibióticos de las colonias identificadas se realizó por el método de difusión en disco de Kirby Bauer. Se lograron identificar 2 especies de bacterias multirresistentes, entre ellas, cepas de Morganella morganii y Plesiomonas shigelloides resistentes a antibióticos de uso clínico como ceftazidima, aztreonam, ciprofloxacino, ácido nalidíxico y trimetroprim-sulfametoxazol. Los resultados muestran que las aguas del río Chibunga albergan bacterias con multirresistencia a los antimicrobianos, representando un riesgo de contaminación de los productos agrícolas cosechados en sus inmediaciones, así como para las personas que utilizan estas aguas.

Abstract The use of fungi and bacteria with pathogenic capacity towards insects is considered a sustainable agroecological alternative for efficient pest control, as they are microorganisms of easy production in industrial scale, formulation and use. Therefore, the objective was to evaluate four entomopathogenic formulations in the control of Brevicoryne brassicae L., a key pest of cabbage (Brassica oleracea L.), in a randomized complete block design with 4 treatments, plus an absolute control and 4 replicates. The variables evaluated were the number of dead and live aphids per plant and the number of infested plants. The commercial formulations Biosafe, BesT-K, Metarrizo and Yurak containing strains of Bacillus subtilis, Bacillus thuringiensis var kurstaki (Btk), Metarhizium anisopliae and Bauveria bassiana respectively, are the ones that were used by spray application to the crop in two seasons: planting, season August-December 2019 and August-December 2021. Among the results, M. anisopliae was recorded with up to 91.11 % efficiency, followed by B. bassiana with 89.50 % and Bs with 79.38 % in the reduction of populations under field conditions. In the laboratory, Btk and M. anisopliae reached 100 % mortality in a period of seven days, so it is concluded that in the medium term, entomopathogenic fungi in the field are more efficient in aphid control; however, in controlled conditions Btk is also efficient.

Resumen El uso de hongos y bacterias con capacidad patogénica hacia los insectos se considera una alternativa agroecológica sostenible de lucha eficiente contra las plagas por ser microorganismos de fácil producción en escala industrial, formulación y uso; entonces, el objetivo ha sido evaluar cuatro formulados entomopatógenos en el control de Brevicoryne brassicae L, plaga clave de la col (Brassica oleracea L.), en diseño de bloques completos al azar de 4 tratamientos, sumado un testigo absoluto y 4 réplicas, siendo las variables evaluadas la cantidad de pulgones muertos y vivos por planta y cantidad de plantas infestadas. Los formulados comerciales Biosafe, BesT-K, Metarrizo y Yurak que contenían cepas de Bacillus subtilis, Bacillus thuringiensis var kurstaki (Btk), Metarhizium anisopliae y Bauveria bassiana, respectivamente, son los que fueron utilizados mediante la aplicación por aspersión al cultivo en dos épocas de siembra, temporada agosto-diciembre 2019 y agosto-diciembre 2021. Entre los resultados se registró al M. anisopliae con hasta 91,11 % de eficiencia, seguida por B. bassiana con 89,50 % y Bs con 79,38 % en la reducción de las poblaciones en condiciones de campo; en laboratorio el Btk y M. anisopliae alcanzaron el 100 % de mortalidad en un lapso de siete días, por lo que se concluye que a mediano plazo los hongos entomopatógenos en campo resultan ser más eficientes en el control del pulgón, sin embargo, en condiciones controladas el Btk también es eficiente.

ABSTRACT Sugarcane-duck symbiosis (SDS) is an ecological breeding production method wherein meat ducks are released in sugarcane (Saccharum officinarum L.) fields during the middle and late stages of sugarcane growth. The effects of SDS on sugarcane rhizobacterial diversity remain poorly understood. We conducted field experiments with sugarcane monoculture (SC) and SDS and performed genetic analyses on the rhizobacterial communities based on 16S rRNA across different growth stages of sugarcane. The effects of soil physicochemical factors on the bacterial community structure were analyzed via redundancy analysis. We found that soil organic matter (SOM), total N (TN), nitrate N (NN), and ammonium N (AN) contents of sugarcane rhizosphere soils increased during different growth periods in SDS. During the perennial root stages, the Shannon-, Ace-, and Chao1 indices increased, whereas the available P (AP) content decreased. The soil pH was more balanced and its effect on the soil bacterial community was insignificant. The dominant sugarcane rhizosphere flora were Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, Firmicutes, norank_f__norank_o__Gaiellales, Sphingomonas, norank_f__Roseiflexaceae, Bacillus, and norank_f__Xanthobacteraceae, but with significant inter-annual variations. Redundancy analysis showed that SOM, TN, NN, AN, AP, catalase (CAT) and invertase (INV) activity were closely associated with the diversity of the soil bacterial communities, and TN and INV activity were the main drivers of sugarcane rhizobacterial communities in the SDS groups. In conclusion, SDS improves the fertilizer supply capacity and soil quality of sugarcane soils by regulating major soil nutrient content, available nutrients, and microbial diversity. This study provides a theoretical basis for scientifically managing SDS and the screening of biocontrol bacteria.

ABSTRACT Due to the diversification of dairy products developed in the state of Falcón, the introduction of a fermented dairy product derived from yogurt combined with Aloe vera gel, a traditional crop of the region, is novel due to its nutritional properties and health benefits. The objective of this research was to evaluate the quality of a dairy drink with fermented aloe according to current regulations. Important authors such as Tamime and Robinson 1, Morillo and Toyo 2, Méndez and Romero 3 were taken as references. Product elaboration runs were carried out on a laboratory scale, in order to establish the adequate proportions of the fruity Aloe gel by mixing fruit pulp, sugar and Aloe gel, the most accepted being the 1:1:1 ratio. The physicochemical and microbiological characterization of the raw material and the finished product was carried out using the COVENIN standards and organoleptic tests to untrained judges to ensure the acceptance of the product, from which a fermented milk drink was obtained with the addition of 50 % gel of Fruity Aloe with a pH of 4,51; a titratable acidity of 0,837 % lactic acid; 3,64 % fat and 12,92 % non-fat solids. Regarding the microbiological quality, few yeasts and the absence of coliform bacteria were found, which complies with the physicochemical and microbiological requirements demanded by the regulations, allowing the obtaining of a quality product suitable for human consumption based on natural raw materials.

RESUMEN Debido a la diversificación de los productos de origen lácteo desarrollados en el estado Falcón, la introducción de un producto lácteo fermentado derivado del yogurt combinado con gel de Aloe vera, cultivo tradicional de la región, es novedoso por sus propiedades alimenticias y beneficios a la salud. Esta investigación tuvo como objetivo evaluar la calidad de una bebida láctea fermentada con gel de Aloe frutado según la normativa vigente. Se tomaron como referencias importantes autores como Tamime y Robinson, (1) Morillo y Toyo, (2) Méndez y Romero. (3) Se realizaron corridas de elaboración del producto a escala de laboratorio, a fin de establecer las proporciones adecuadas del gel de Aloe frutado mezclando pulpa de fruta, azúcar y gel de Aloe, siendo la más aceptada la proporción 1:1:1. Se realizó la caracterización fisicoquímica y microbiológica de la materia prima y del producto terminado mediante las normas COVENIN y pruebas organolépticas a 10 jueces no entrenados para asegurar la aceptación del producto, de donde se obtuvo una bebida láctea fermentada con la adición de 50 % de gel de Aloe frutado con un pH de 4,51; una acidez titulable de 0,837 % de ácido láctico; 3,64 % de grasa y 12,92 % de sólidos no grasos. Respecto a la calidad microbiológica se encontraron levaduras escasas y ausencia de bacterias coliformes, con lo cual se cumple con los requisitos fisicoquímicos y microbiológicos exigidos por la normativa, permitiendo la obtención de un producto de calidad apto para el consumo humano a base de materias primas naturales.

RESUMEN Introducción: Las infecciones de sitio quirúrgico están asociadas con infecciones relacionadas a la asistencia sanitaria (IRAS), causadas por bacterias que ingresan a través de las incisiones efectuadas durante un procedimiento quirúrgico. Objetivo: Describir la frecuencia y características de las infecciones de sitio quirúrgico en las cirugías de urgencias en pacientes pediátricos hospitalizados en el Hospital General Pediátrico. Materiales y Métodos: Estudio observacional descriptivo, retrospectivo, de corte transversal. Población: Pacientes de 0 a 18 años sometidos a intervención quirúrgica abdominal de urgencia. Variables estudiadas: Edad, Sexo, Procedencia, Comorbilidad, reingreso hospitalario, tiempo trascurrido entre la intervención quirúrgica y la aparición de la infección en sitio quirúrgico. Datos obtenidos del análisis de fichas clínicas y la base de datos del HIS en el paquete estadístico SPSv23 (IBM SPSS, DEMO) utilizando estadística descriptiva. Resultados: Fueron incluidas 440 fichas de pacientes, la mediana de edad fue de 10 años, el 60,5% fueron del sexo masculino y el 71,4% procedían del Departamento Central. Se observó que el diagnóstico más frecuente fue peritonitis de origen apendicular 53,2%. El estado nutricional de la población en estudio fue normal en 93,2%, y fueron reingresos el 3% de los pacientes intervenidos. Presentaron infección de sitio quirúrgico el 4,8%, de los cuales 11/21 fueron absceso de pared. En cuanto al tiempo trascurrido entre la cirugía y la aparición de la infección la mediana fue de 14 días. Conclusión: La frecuencia de infección del sitio quirúrgico encontrada en este estudio fue del 4,8%. La patología quirúrgica con mayor porcentaje fue la peritonitis y el tipo de infección absceso de pared. La mayoría de los pacientes eran escolares con buen estado nutricional.

ABSTRACT Introduction: Surgical-site infections are associated with healthcare-associated infections (HAIs), caused by bacteria that enter through the incisions made during a surgical procedure. Objective: To describe the frequency and characteristics of surgical site infections in emergency surgeries in pediatric patients hospitalized at a Pediatric General Hospital. Materials and Methods: This was a descriptive, retrospective and cross-sectional observational study. Population: Patients aged 0 to 18 years undergoing emergency abdominal surgery. Variables studied: Age, Sex, Origin, Comorbidity, hospital readmission, time elapsed between the surgical intervention and the appearance of the surgical site infection. Data obtained from the analysis of clinical records and the electronic health record database in the SPSv23 statistical package (IBM SPSS, DEMO) using descriptive statistics. Results: 440 patient records were included, the median age was 10 years, 60.5% were male and 71.4% came from the Central Department. It was observed that the most frequent diagnosis was peritonitis of appendiceal origin 53.2%. The nutritional status of the study population was normal in 93.2%, and 3% of the operated patients were readmitted. 4.8% had surgical site infection, of which 11/21 were wall abscesses. Regarding the time elapsed between surgery and the appearance of the infection, the median was 14 days. Conclusion: The frequency of surgical-site infection found in this study was 4.8%. The surgical pathology with the highest percentage was peritonitis and the wall abscess type of infection. Most of the patients were schoolchildren with good nutritional status.

Abstract The objective of this research was to identify bacteria present in the microbiota of dentinal carious lesions in primary molars of some Costa Rican pediatric patients. Data were collected from 15 children aged between 4 and 8 years old who attended the Pediatric Dentistry Clinic at the Faculty of Dentistry from the University of Costa Rica (UCR). The inclusion criteria were: infants between 4 and 8 years old who presented cavitated carious lesions in primary teeth, who were actively attended by students at the Faculty of Dentistry from the UCR, and whose parents or legal guardians signed the informed consent to participate in this research. Samples were taken using a sterile spoon, placed in storage vials, and subjected to various conventional and molecular microbial identification techniques, such as Gram stain identification, catalase tests, oxidase, TSI, API 20E, API STAPH, and VITEK 2. Of the 60 bacterial strains subjected to Gram staining, the following was obtained: 28 Gram-positive bacteria and 32 Gram-negative bacteria. The main isolated organisms were species of Staphylococcus epidermidis, Pasteurella pneumotropica/Mannheimia haemolytica, Pantoea spp, and Streptococcus mutans.

Resumen El objetivo de esta investigación fue identificar las bacterias presentes en la microbiota de lesiones cariosas dentinales en molares primarias de pacientes pediátricos costarricenses. Las muestras fueron recolectadas de 15 niños entre los 4 y 8 años que fueron atendidos en la Clínica de Odontopediatría en la Facultad de Odontología de la Universidad de Costa Rica (UCR). Los criterios de inclusión fueron: pacientes entre los 4 y los 8 años de edad que presentaran lesiones cariosas cavitadas en dientes primarios, que se encuentraran activos para su atención por estudiantes de la Facultad de Odontología de la UCR, y que los padres o encargados legales firmaran el consentimiento informado para participar en esta investigación. Las muestras se tomaron utilizando una cuchareta estéril, colocándolas en viales de almacenamiento y fueron sometidas a diversas técnicas de identificación microbiana convencionales y moleculares tales como: identificación por Tinción de Gram, pruebas catalasa, oxidasa, TSI, API 20E, API STAPH y VITEK. De las 60 cepas bacterianas sometidas a tinción de Gram se obtuvo: 28 bacterias Gram Positivas y 32 bacterias Gram Negativas. Los principales organismos aislados fueron: especies de Staphylococcus epidermidis, Pasteurella pneumotropica/ Mannheimia haemolytica, Pantoea spp y Streptococcus mutans.

Abstract: Utilization of microbiologically induced calcite precipitation along with fiber composite have great influence on improving strength and durable properties of concrete. The concept of mechanical properties of grouted concrete added with bacteria, steel fibers (SF), rice husk ash (RHA) and light weight aggregate (LWA) has been focused on this work. In the fabrication of concrete specimens, concentration of bacteria, combination of steel fibers and LWA was placed in the form-work, and to fill the voids flowable grout was injected. The variables studied in this work are two different sizes of LWA viz., 10 mm and 12.5 mm with constant dosage of 2% hooked end steel fibers by volume of concrete, 10% RHA was used as cement replacement for preparation of grout and bacteria was incorporated in cement grout by direct application. The prop erties such as compressive strength (CS), compressive strength regain (CSR), crack width healing, impact strength for first crack and final failure, rate of healing was studied for pre-cracked specimens using visual and microscopic observation. In addition, microstructure was studied for grouted concrete without bacteria and with bacteria under immersed curing condi tions. From the experimental results, performance of bacteria added grouted concrete properties such as CS, CSR, cracking healing capacity, and impact strength has improved with the addition of fibers

Abstract: Soil nitrogen is crucial for agriculture, but it is often limited, affecting crop yields. Deficiency requires synthetic fertilizers, but their improper use results in environmental damage and high costs. Bacteria of the genus Rhizobium, symbionts of legumes, offer a sustainable solution by fixing nitrogen, thus reducing dependence on fertilizers. This research determined the most probable number (MPN) of cells of Rhizobium spp. from two commercial biofertilizers of Ecuadorian and Mexican origin under greenhouse conditions. For this, direct inoculation with serial dilutions (10-1 to 10-10) was performed in pots with steam-sterilized pumice where Blue Lake variety snap bean (Phaseolus vulgaris L.) plants were germinated. The following morphological indicators were evaluated at 45 days after sowing (DAS): leaf area, plant wet weight, plant height, and number of flowers, determining statistical differences between the type of biofertilizer and the concentration of each dilution. The experiment followed a randomized complete block design with a split-plot arrangement, with three replicates per dilution, considering temperature fluctuations in the study area. The MPN at 95% confidence was 4.45x107 rhizobia g-1 of pumice at a 10-5 dilution for the Mexican biofertilizer, and 1.48x105 rhizobia g-1 of pumice at a 10-4 dilution for the Ecuadorian biofertilizer. The estimated optimal dilution for both products was 10-8.

Resumen: El nitrógeno en el suelo es crucial para la agricultura, pero a menudo es limitante, afectando el rendimiento de los cultivos. La deficiencia requiere fertilizantes sintéticos, pero su uso inadecuado causa daños ambientales y costos elevados. Las bacterias del género Rhizobium, simbiontes de leguminosas, ofrecen una solución al fijar nitrógeno de manera sostenible, reduciendo la dependencia de fertilizantes. Esta investigación determinó el número más probable (NMP) de células de Rhizobium spp. procedente de dos biofertilizantes comerciales de origen ecuatoriano y mexicano en condiciones de invernadero. Para esto, se realizó la inoculación directa con disoluciones seriadas (10-1 a 10-10) en macetas con pomina esterilizada al vapor, donde se germinaron plantas de frijol ejotero (Phaseolus vulgaris L.) de la variedad Blue Lake. A los 45 días después de siembra (DDS) se evaluaron los siguientes indicadores morfológicos: área foliar, peso de la planta en húmedo, altura de planta y número de flores, determinándose diferencias estadísticas entre el tipo de biofertilizante y la concentración de cada dilución. El experimento se adecuó a un diseño de bloques completos al azar con arreglo de parcela dividida con tres repeticiones por dilución, en consideración de las fluctuaciones de temperatura presentes en la zona de estudio. El NMP, al 95% de confianza, fue de 4,45x107 rizobios g-1 de pomina en una dilución 10-5 para el biofertilizante mexicano, y 1,48x105 rizobios g-1 de pomina en una dilución 10-4 para el biofertilizante ecuatoriano. La dilución óptima estimada para ambos productos fue de 10-8.

Abstract: Solid and liquid formulations based on the plant growth-promoting bacteria Bacillus subtilis Bs006 were designed as biological inoculant for vegetable nursery production. Considering the importance of microbial survival from the production process to the soil application, spore viability (CFU) in each formulation was assessed during twelve months of storage at 20, 30, and 40°C. At the three temperature levels evaluated, survival was higher than 85 and 90% for solid and liquid formulations, respectively. The bacterial biological activity was evaluated as plant growth promotion on lettuce, broccoli, and tomato in nursery. The formulations were applied at three concentrations (1x107, 5x107, 1x108 CFU/mL) at sowing and 21 days after seeding. Root and aerial part length and dry weight were the response variables evaluated. A positive effect was observed, particularly with the liquid formulation at 1x108 spores/mL, showing the longest length of root and aerial part and the highest dry weight values in the root and foliar parts. Regarding the endophytism, B. subtilis colonized roots, stems, and leaves, achieving concentrations between 8x102 and 1x105 CFU/g.

Abstract A previously healthy 16-year-old male with a ten-day history of proptosis and pain in the left upper eyelid and inflammatory signs of the left lower limb, without fever, was admitted to the Emergency Department. Computed tomography (CT) scan revealed an extensive intraorbital lesion and a multiloculated collection in the muscle planes of the thigh. The boy underwent surgical drainage and was started on empiric antibiotics. Methicillin-susceptible Staphylococcus aureus was isolated from blood and exudate cultures. Because the boy remained febrile, a chest CT scan was performed, which revealed bilateral cavitary lung lesions. He completed a long course of antibiotherapy. The study for potential immunodeficiency disorders was unremarkable. Most pediatric cases of community-associated Staphylococcus aureus bacteremia are associated with a localized source of infection. Diagnosis depends on isolation from blood and fluid aspirates. Treatment usually requires surgical drainage and intravenous antibiotherapy. Staphylococcus aureus bacteremia may be associated with multiple foci of infection, which should be recognized promptly.

Resumo Um adolescente do sexo masculino de 16 anos de idade, previamente saudável, foi admitido no Serviço de Urgência por proptose e dor na pálpebra superior esquerda e sinais inflamatórios no membro inferior esquerdo, sem febre, com dez dias de evolução. A tomografia computorizada (TC) revelou uma lesão expansiva intraorbitária e coleção multiloculada nos planos musculares da coxa. O rapaz foi submetido a drenagem cirúrgica e iniciou antibioterapia empírica. A hemocultura e cultura dos exsudados permitiram o isolamento de Staphylococcus aureus sensível à meticilina. Dado que o rapaz continuava febril, foi realizada TC torácica, que evidenciou lesões pulmonares cavitadas bilateralmente, tendo sido efetuado um esquema prolongado de antibioterapia. O estudo de potenciais imunodeficiências foi negativo. A maioria dos casos de bacteremia a Staphylococcus aureus na comunidade estão associados a focos infeciosos localizados. O diagnóstico requer isolamento no sangue ou exsudados. A abordagem implica drenagem cirúrgica e antibioterapia endovenosa. A bacteremia a Staphylococcus aureus pode associar-se a múltiplos focos de infeção, pelo que deve ser precocemente reconhecida.

Resumo Objetivos: O objetivo desta revisão sistemática foi reunir estudos que utilizam o extrato de própolis para o controlo da atividade antimicrobiana e avaliar sua atividade in vitro contra os principais periodontopatógenos. Métodos: Foi realizada uma busca nas bases de dados PubMed/MEDLINE, Scielo, Lilacs, Science Direct, Cochrane, SCOPUS, Web of Science e na literatura cinzenta (Google Scholar and OpenGrey), complementada por uma busca manual, e foram incluídos artigos que atenderam aos critérios: estudos in vitro que avaliaram a ação da própolis contra pelo menos um periodontopatógeno. Resultados: A busca na base de dados resultou em 1473 artigos. Após análise dos títulos e resumos, 179 artigos estavam duplicados, 18 artigos foram selecionados para triagem do texto completo e cinco deles foram excluídos. A busca manual resultou em um artigo. Esta revisão sistemática compreendeu 13 artigos. A Porphyromonas gingivalis apareceu em todos os estudos e a própolis apresentou efeito antibacteriano demonstrando a partir da concentração inibitória mínima. Conclusões: O extrato de própolis apresenta atividade antimicrobiana efetiva sobre as bactérias patogénicas periodontais, podendo ser uma opção terapêutica viável para a modulação da periodontite. Mais estudos são importantes para analisar os efeitos citotóxicos de diferentes concentrações nos fibroblastos gengivais.

Abstract Objectives: The aim of this systematic review was to gather studies that use propolis extract to control antimicrobial activity and evaluate its activity in vitro against major periodontopathogens. Methods: A search of the PubMed/MEDLINE, Scielo, Lilacs, Science Direct, Cochrane, SCOPUS, Web of Science, and gray literature (Google Scholar and OpenGrey) databases was performed, complemented by a manual search. Articles meeting the following criteria were included: in-vitro studies that evaluated the action of propolis against at least one periodontopathogen. Results: The database search resulted in 1473 articles. After analysis of the titles and abstracts, 179 articles were duplicated, and 18 were selected for full-text screening, of which five were excluded. The manual search resulted in one article. This systematic review comprised 13 articles. Porphyromonas gingivalis appeared in all studies, and propolis showed na antibacterial effect, demonstrating the minimum inhibitory concentration. Conclusions: The propolis extract shows an effective antimicrobial activity on the periodontal pathogenic bacteria and may be a viable therapeutical option for the modulation of periodontitis. More studies are important to analyze the cytotoxic effects of different concentrations on gingival fibroblasts.

Abstract Faced with the challenges posed by the need for fertilizers to maintain agricultural production, a biological process of atmospheric nitrogen fixation occurs naturally, which is carried out by a group of symbiotic bacteria that form a very close association with plants of the legume group, among which is the sweet clover (Melilotus spp.). From an ecological point of view, this plant has an essential function due to its good ability to associate with native nitrogen-fixing bacteria of the genus Sinorhizobium. A fundamental aspect is that this plant species can grow normally in alkaline soils, which doubles its importance since, on the one hand, it fixes nitrogen, and on the other hand, it can be incorporated as green manure. With this, the physicochemical properties of the soil are improved, and the levels of organic matter, which is in extremely poor condition in arid zone areas, are increased. Additionally, this species can withstand low temperatures and grow satisfactorily in winter. This paper presents a synthesis of the genus Melilotus and its symbiont Sinorhizobium meliloti and its importance as a potential natural soil improver.

Resumen Ante los retos por la necesidad de fertilizantes para mantener la producción agrícola, ocurre naturalmente un proceso biológico de fijación de nitrógeno atmosférico por parte de un grupo de bacterias simbióticas que forman una asociación muy estrecha con plantas del grupo de las leguminosas, entre las que se encuentran las alfalfillas o tréboles silvestres (Melilotus spp.). Desde el punto de vista ecológico esta planta tiene una función muy importante por la buena capacidad de asociarse a bacterias nativas del suelo fijadoras de nitrógeno del género Sinorhizobium. Un aspecto fundamental es que esta especie vegetal puede crecer normalmente en suelos alcalinos, lo que le convierte aún más como doble importante, ya que, por un lado, fija nitrógeno y por el otro puede incorporarse como abono verde. Con ello, se mejoran las propiedades físico-químicas del suelo y, se incrementan los niveles de materia orgánica, condición que es muy pobre en las áreas de zonas áridas. Adicionalmente, esta especie puede resistir bajas temperaturas y crecer satisfactoriamente en invierno. Este documento presenta una síntesis del género Melilotus y su simbionte Sinorhizobium meliloti, así como su importancia como posible mejorador natural del suelo.

Resumen La interacción entre SARS-CoV-2 e infecciones invasivas por bacterias capsuladas (IIBC) continúa bajo estudio. Objetivos: comparar la incidencia de IIBC antes y durante la pandemia por COVID-19, evaluar la incidencia de coinfección con COVID-19 y la letalidad. Estudio transversal de registros de un laboratorio centralizado de Microbiología, que asiste a una red de centros asistenciales con 713 camas de internación para adultos y pediátricos, expandida 20% durante la pandemia. Tres periodos evaluados: 1) Pre-pandemia: 1-Marzo-2019 al 29-Febrero-2020; 2) Primer año de Pandemia: 1-Marzo-2020 al 28-Febrero-2021; 3) Pandemia 2021: 1-Marzo-2021 al 31-Julio-2021. Análisis estadístico descriptivo: Se analizaron 56.502 muestras (96% hemocultivos) correspondientes a 27.224 pacientes. De estas, 54 muestras (de 54 pacientes) fueron positivas para bacterias capsuladas. La incidencia de IIBC fue 167,4, 32,6 y 50,4 por cada 100.000 muestras para los periodos 1, 2 y 3, respectivamente. Doce IIBC ocurrieron durante la pandemia: 10 Streptococcus pneumoniae y dos Haemophilus influenzae, siete de ellos corresponden a coinfección SARS-CoV-2/S. pneumoniae, con una incidencia de 5,68 por cada 10.000 internaciones por COVID 19 (0,056%). La letalidad de las IIBC fue de 31, 29 y 60% para los tres periodos, respectivamente, 3/7 coinfectados fallecieron (43%). La letalidad por enfermedad neumocócica invasiva (ENI), sin COVID fue de 32,5%. Se evidenció una reducción significativa de la incidencia de IIBC luego del comienzo de la pandemia, coincidente con la implementación de las medidas sanitarias de contención de la pandemia. La incidencia de coinfección de SARS-CoV-2/S. pneumoniae fue baja y presentó mayor letalidad que las ENI sin COVID-19.

Abstract Interaction between severe acute respiratory coronavirus 2 (SARS-CoV-2) and IIEB remains under investigation. Objective: to compare IIEB incidence before and during COVID-19 pandemic, and assess incidence of coinfection with COVID-19 and case fatality. A cross-sectional study was performed on data from a centralized microbiology laboratory serving a network of healthcare centers comprising 713 pediatric and adult inpatient beds, expanded by 20% during the pandemic. Three periods were evaluated: (1) pre-pandemic: March 1, 2019-February 29, 2020; (2) pandemic year 1: March 1, 2020-February 28, 2021; (3) pandemic year 2: March 1, 2021-July 31, 2021. Descriptive statistical analysis was performed. 56502 samples (96% blood cultures) from 27224 patients were analyzed. Of these, 54 samples (from 54 patients) were positive for encapsulated bacteria. IIEB incidence was: 167.4, 32.6, and 50.4 per 100000 samples for periods 1, 2, and 3, respectively. Twelve IIEB episodes occurred during the pandemic period: 10 Streptococcus pneumoniae, and 2 Haemophilus influenzae, of which 7 were SARS-CoV-2/S. pneumoniae coinfections, with an incidence of 5.68 per 10000 COVID-19-related hospitalizations (0.056%). IIEB case fatality was 31%, 29%, and 60% for each period, respectively, 3/7 patients with coinfection died (43%). Case fatality for invasive pneumococcal disease (IPD) in patients without COVID-19, was 32.5%. Significant reduction in IIEB incidence was observed during the pandemic, coinciding with implementation of containment measures. The incidence of SARS-CoV-2/S. pneumoniae coinfection was low, with higher case fatality than IPD patients without COVID-19.